LOS ANGELES — Michael Jackson likely injected himself with a fatal dose of the anesthetic propofol after popping an extra eight sedatives without his doctor’s knowledge, jurors were told yesterday.

Dr. Paul White, the last defense witness in the involuntary-manslaughter trial of the singer’s doctor, Conrad Murray, said self-administration was the likeliest scenario.

White said that, based on the amount of propofol found in Jackson’s urine, he believed the pop star gave himself a further injection of propofol about one hour after Murray has admitted injecting him with a relatively small 25-milligram dose of the drug.